Destination out of order from ISDN PRI

[225513057M]

I have a cisco router 2921 series with Vwic3-T1/E1 conected to o cisco GW and then a CUMC, when an IPphone is OFline and I call it from my mobile the GW sends the message "destination out of order" but the CPE still sends an invite message to the CUM and I don't hear the busy tone I only hear a silence. please the customer wants hear the Busy Tone on the mobile phone how I can resolve this problème???. can somebody help me?

Thanks.

[kkoeper12 · Accepted solution]

Why not fill in the Call Forward Unregistered field on the line of the phone that is not registered and send it to the user's voicemail?

What is the integration from CUCM and the gateway? MGCP, H323, SIP? What version CUCM are you using?